The present invention relates to seals, often referred to as gaskets, for making a fluid or gas tight joint between opposed mating surfaces. More particularly, the present invention relates to retainers for positioning seals between opposed mating surfaces.
Ring seals are typically annularly shaped, defining an axially aligned hole for gas or fluid passage, two axially opposed end surfaces, a radial inner surface and a radial outer surface. The most simplistic ring seal includes planar end surfaces and smooth circular radial inner and outer surfaces which define the inner diameter (ID) and outer diameter (OD) of the ring seal.
An additional commonly used ring seal is circular and has a radial cross-section of a “C” shape. These “C seals” are constructed with the open side of the C construction facing the center of the ring such as described in U.S. Pat. No. 5,354,072, or with the open side of the C facing away from the center of the ring. As two mating surfaces are brought together with the C seal in the middle, the C seal is compressed with the open side of the C cross-section closing during compression. The ductile properties of the seal permit plastic deformation to occur without damaging the mating surfaces.
Additional seals which have been available include “V seals” which are also circular, but instead of having a “C” cross-section, the V seal has a “V” cross-section with the low point of the V constructed to point either inwardly or outwardly towards the center of the seal. Moreover, seals in the art include “Z seals” and simple “O rings”.
With reference to FIGS. 1 and 4, many typical ring seals 1 include an annular body configuration and a circumferential groove 15 formed on the ring seal's outer radial surface. In addition, many ring seals include a recessed sealing surface 19 formed into each of the axial end surfaces. In operation, the opposed mating surfaces of the sealing assembly engage and form an air or fluid tight seal at the ring seal's recessed sealing surface. However, the opposed mating surfaces typically do not engage or form a seal at the ring seal's recessed regions. The sealing surface is recessed to protect the surface from becoming damaged during handling. For example, ring seals having planar surfaces often become scratched when placed on flat surfaces due to dirt or metal shavings scratching the ring seal's sealing surface. To overcome this drawback, the ring seal's sealing surface is recessed so as to not come into contact with debris prior to assembly within a sealing assembly. Unfortunately, ring seals having recessed sealing surfaces are expensive to manufacture and the recessed sealing surface is very difficult to polish.
Retainers are often used to hold and position a ring seal in place between two opposed mating surfaces. Retainers have been constructed in various forms. For example, U.S. Pat. No. 5,340,170 describes a retainer for positioning a gasket in a pipe joint. The retainer includes a cylindrical sidewall, an inwardly extending edge for engaging a ring seal and a plurality of claws for grabbing a pipe.
Meanwhile, U.S. Pat. No. 5,423,580 discloses a retainer having a semicircular sidewall for grasping the outer edge of a ring seal and extremity of a pipe. Moreover, additional retainer arrangements are disclosed in U.S. Pat. Nos. 4,552,389; 4,650,227; and 4,838,583.
An additional prior art ring seal and retainer assembly is shown in FIGS. 1-4. The ring seal includes a typical annular body configuration and circumferential groove formed on the ring seal's outer radial surface. In addition, the ring seal includes a recessed sealing surface 19 formed on each of the axial end surfaces. The retainer is obtained from a single loop of a coil spring, which is then formed into a circular band. The coil retainer is positioned within the ring seal's circumferential groove so that the outer edge of the coil projects outwardly beyond the edge of the ring seal. Meanwhile, the opposed mating surfaces include a fitting including a recess sized and positioned for receipt of the coil retainer's edge. Once press fit into place, the retainer is restrained from inadvertent movement.
Unfortunately, the above-described retainers all suffer from significant disadvantages. For example, the coil retainer and sharp edges of the ring seal are prone to scratching, or otherwise harming, the opposed mating surfaces. This can impede the ring seal's ability to provide a gas or fluid tight seal. Moreover, ring seals having a recessed sealing surface are expensive to manufacture. Meanwhile, the retainer described in U.S. Pat. No. 5,340,170 is capable of use only with a ring seal of an unusual construction. Furthermore, the retainer disclosed in U.S. Pat. No. 5,423,580 also does not protect the edge of a ring seal from unwantingly scratching one of the opposed mating surfaces.
An additional disadvantage of present ring seal and retainer assemblies is that the ring seal must be positioned and aligned very precisely with the gaseous passageway. Any misalignment can cause the ring seal to fail and excessively leak. Unfortunately, present ring seal and retainer assemblies do not provide a structure for automatically positioning and aligning the ring seal between opposed mating surfaces.
Thus, it would be desirable to provide an improved ring seal and retainer assembly which is inexpensive to manufacture and easy to use.
In addition, it would be desirable to provide an improved ring seal and retainer assembly which does not require recessed sealing surfaces which are expensive to manufacture and difficult to polish.
Moreover, it would be desirable to provide an improved ring seal and retainer assembly which provides protection against damage to a ring seal's sealing surfaces, while not being susceptible to scratching or otherwise marring the opposed mating surfaces prior to forming an air-tight or gas-tight seal.
It would also be desirable to provide a ring seal and retainer that provide for precise positioning and alignment of the ring seal prior to forming a gaseous tight joint between opposed mating surfaces.